Life-lock
by felicityredbarrow
Summary: The Doctor and Jo struggle to understand the physiology of a six-year-old girl they find in the woods.
1. Chapter 1

** That dream again.**

**The Doctor's eyes fluttered open as he realized he had (once again!) fallen asleep at one of the tables in the lab. He lifted a hand and was mildly startled by a small **_**ping! **_**as a tiny gear from his latest project hit the table. Turning his wrist over, he inspected the small imprint where the tiny piece had stuck to his skin.**

**"Doctor! You're awake! How are you feeling?" It was Jo carrying a tray with a pot of tea, two cups, and some sandwiches. **

**"A bit better, my dear, thank you." It was true; he was feeling a bit better in comparison to the last two days. The Doctor straightened up, and a standard army-issue wool blanket slid off his shoulders to land in a crumpled heap on the laboratory floor.**

**"Oh," Jo set down the tray and picked up the blanket, "I had Sergeant Benton bring it down after you fell asleep. You won't get over your cold if you don't keep warm." She gave him a cheerful smile, "I brought you some lunch, you should eat something."**

**The Doctor rubbed the back of his neck sheepishly. He didn't much enjoy being fussed over, but he did appreciate Jo's concern. He really had been feeling dreadful, and she had been there for him all the while, so he smiled appreciatively as she poured him a cup of tea.**

**"Sugar?" she asked.**

**"Two, please," he managed to say before deftly pulling out an olive handkerchief to stifle a violent sneeze. **

**"Bless you, Doctor!" Jo insisted, looking at him as if he were a half-drowned kitten. **

**"Still under the weather, Doc?" Sergeant Benton strode into the room looking sympathetic as the Doctor blew his nose.**

**"He says he's feeling a bit better," Jo piped up helpfully.**

**The Doctor frowned impatiently. "Lethbridge-Stewart send you down to check on me, did he?"**

**Benton grinned. "Actually, I overheard him telling Captain Yates to come down to check on you, the Captain turned right around and sent me. Reckon he's afraid of catching it."**

**The Doctor shook his head, "We've been over this. Humans and Time Lords aren't closely enough related to share illnesses. Gallifreyan viruses evolved alongside gallifreyans just like Earth viruses evolved alongside earthlings here, but they're incomparable. I can't catch your colds, and you can't catch gallifreyan colds."**

**"But, Doctor," Jo piped up again, "how did you catch a cold? You haven't been near the Time Lords."**

**"The Master." Benton stated simply.**

**The Doctor rubbed his nose, "Yes, I thought he wasn't looking quite well last time we saw him. If he hadn't given it to me, I'd have felt sorry for the poor chap, but as it is..." He trailed of, reaching for his handkerchief. "Ah**_**-CHOO!"**_

**Now it was the Brigadier's turn to stride into the room uninvited. "Bless you, Doctor," he said politely.**

**Frustrated, the Doctor stood up and shoved the handkerchief back into his coat pocket. "Good grief! Haven't you lot all got something better to do than watch me blow my nose?" **

**The Brigadier allowed an eyebrow to meet up with his hairline as his thin mustache curled into a restrained smile. The Doctor was snapping at him; a good sign. "Actually, Doctor, things seem to be rather quiet lately." Lethbridge-Stewart rocked back on his heels holding his hands comfortably behind his back. "Apart from your sneezing, that is." His smile grew less restrained.**

**The Doctor ruffled, indignant as a peacock, which got an amused smile from Jo while Sergeant Benton tried not to laugh aloud. "How very base, Brigadier! You know I can't... c-can't help-!" The Doctor rubbed his nose in aggravation. "Oh! Ah**_**-CHOO!" **_**He sneezed again, earning him another "Bless you!" from his colleagues. He glared at the Brigadier from behind his handkerchief. **

**To his abasement, Jo draped the wool blanket over his shoulders. "Look, I have rather a lot of work to do, and I don't need a bunch of tin soldiers mucking about, so if you could kindly leave, I'd most appreciate it."**

**The Brigadier, satisfied that the Doctor was making progress with his health, turned on his heel, "Come along, Benton. Take care, Doctor; do get some rest." He nodded to Jo, "Look after him. Ms. Grant." She nodded, and the two army men left the lab.**

**As soon as they had gone, the Doctor sank back into his chair, nursing his bruised ego. Taking a sip of his tea, he noticed Jo looking at him with concern. He smiled kindly, "Don't worry, my dear. I **_**am**_** recovering. I'm still just a little worn out, is all.**

**The concern didn't leave Jo's face; she bit her lip, "It's just... Well..."**

**"What is it, my dear?"**

**Jo sighed, "I've just never seen you look so tired."**

**"Oh, honestly, Jo, you worry too much!" The Doctor took one of the sandwiches from the tea tray, stopping midway. **

**Jo frowned, "What is it, Doctor? Oh! I'd wondered where that had gotten to." She carefully pulled a newspaper out from under the plate of sandwiches.**

**The Doctor stood up suddenly, coming around to Jo's side of the table. "Jo, how long have you had that newspaper?"**

**"What do you mean? It's today's paper."**

**"Adelaide Redbarrow," the Doctor whispered, lightly touching a black and white photograph of a child. **

**"Yes, it says here she was reported missing yesterday- Doctor where are you going?"**

**The Doctor was hastily throwing on his driving coat and cape. "Jo, you don't understand! I saw her!"**

**Jo looked bewildered, "You've met her?"**

**"No!" The Doctor buttoned his coat impatiently, "I dreamt about her!"**

**"But you couldn't possibly have-!"**

**"Jo!" The Doctor put his hands on her shoulders and looked her in the eye, "I know." He turned on his heel and hurried out of the lab.**

**"Doctor, what on Earth are you doing?" the Brigadier snapped indignantly as the Doctor rushed past him, nearly knocking him over. "Where are you going, man?"**

**"Infirmary!" the Doctor called without missing a beat.**

**"Infirmary?" Lethbridge-Stewart cocked an eyebrow and took off after his scientific adviser, "But I thought you were feeling better!"**

**"He's worse, Brigadier!" Jo replied urgently as she caught up to him. "He thinks he's looking for that missing girl!"**

**The Brigadier looked even more bewildered, "What missing girl?" Jo held up the newspaper as they both jogged down the hall. "What? That missing girl? Why ever should he think **_**he's**_** looking for her?"**

**"He said something about a dream,"**

**"Must've realized he's taken a turn for the worse. Gone to admit himself, poor chap," the Brigadier reasoned as he and Jo came through the doors of the infirmary."**

**"My dear Brigadier, I most certainly haveNOT taken a turn for the worse!" To Jo and the Brigadier's astonishment, they found the Doctor rifling through cabinets and drawers of the sick bay supply room.**

**"What are you looking for, Doctor?" Jo asked uneasily.**

**"A thermometer, my dear. I've misplaced mine, and I had thought it would be easier to find one here, but there doesn't seem to be any rhyme or reason to this lot. Anyway, if I've still got a lingering fever, that could explain a few things.**

**"Let me see, Doctor," Jo placed the back of her hand to the Doctor's forehead. He sighed and indulgently stood still until Jo pulled her hand away and gasped in alarm. "Doctor! You can't possibly have a fever; you're ice cold!"**

**"Fifteen point six degrees Celsius is far from 'ice cold', Jo," the Doctor opened another cabinet, "That's the average normal temperature for a Gallifreyan. Aha! Here we are, at last!" Taking the thermometer out of its case, he shook it down like a true MD and placed it in his mouth.**

**The Brigadier sighed impatiently when the Doctor finally pulled out the thermometer and studied it carefully. "Well?"**

**The Doctor swabbed the end with a disinfectant and placed the thermometer back in its case. "Slight fever, Brigadier," he announced. "Just as well; I never did like coincidences. Come along, Jo."**

**"Now where are you off to?" asked the Brigadier with the air of one long suffering as he followed the Doctor out of the infirmary. **

**"To get some rest?" Jo provided hopefully.**

**The Doctor frowned, "Don't be silly, Jo. We've got to find that girl!"**

**Lethbridge-Stewart rolled his eyes, "Good Lord, here we go again!"**

**"Doctor, you just proved yourself that you're still not well," Jo pointed out.**

**"I'm well enough!" The Doctor stopped in his tracks, squeezing his eyes shut. He ducked into his sleeve and sneezed twice.**

**"Besides, this is a top secret military establishment with the only purpose to investigate strange goings on. How does a missing child have anything to do with us?"**

**The Doctor wiped his nose and frowned at his colleague. "My dear Lethbridge-Stewart, I should have thought that was perfectly obvious.**

**The Brigadier massaged his temples in frustration. "Doctor, I still don't understand what you're talking about."**

**The Doctor sighed and glanced at Jo, who confirmed her own incomprehension with a small nod. "All right, then, from the top," he said patiently. "My kind are slightly telepathic. Well, much more telepathic than humans."**

**"You mean you could read my mind?" Jo asked in amazement.**

**The Doctor smiled, "No. Well, not easily, anyway. Humans are somewhat telepathic, but usually mostly by accident. What little ability you have as children, you often come to shield as adults." He rested his elbows on the lab table. "It's a similar situation for my kind, only less pronounced. We learn to control the ability with a sort of 'psychic shielding', if you will. But it tends to break down when one is unconscious or weak."**

**"That is all very well, Doctor, but I still don't understand where this girl comes in," the Brigadier leaned on the lab table irritably.**

**"I made a psychic link with her, so to speak." the Doctor stated simply.**

**Jo frowned, "But I thought you said you couldn't read human minds."**

**The Doctor rubbed the back of his neck, "Well, as I said, children have higher psychic ability than adults, and I haven't exactly been..." he cleared his throat, "well..."**

**Jo's eyes brightened, "Of course! That's why you saw her in your sleep!"**

**"So, you're telling me that you saw where that girl is?" The Brigadier paced away from the table.**

**"Well, not exactly, Brigadier," the Doctor stood up and started toward the door of the lab.**

**The Brigadier raised his eyebrows, "Well then how in blazes do you plan to find her?"**

**Pausing a moment, the Doctor looked over his shoulder, "I'm afraid that's a little more difficult to explain. You'll just have to trust me." His eyes shifted to his assistant, "Coming, Jo?"**

**The Brigadier watched the pair leave the laboratory, shaking his head. If the Doctor wanted to play bloodhound, fine. As long as there was nothing else that required his attention, of course. He had to admit that the Doctor usually knew what he was doing, and although it wasn't his concern officially, the Brigadier couldn't help but feel sympathy for the family missing a child. If the Doctor could bring the poor girl home... **

**Lethbridge-Stewart glanced at the old police box in the corner of the lab. "Good luck, Doctor."**

**"How?' **

**The Doctor raised his eyebrows as he helped Jo into the yellow roadster. "How what?" **

**Jo waited until he climbed into the driver's seat before elaborating, "How are you going to find her?"**

**"Well, as I said, it's difficult to explain."**

**"But you would try unless..." She gave him a stern look, "You don't know, do you!"**

**The Doctor rubbed the back of his neck sheepishly, "That isn't entirely true, Jo. I know that I can do it, but as to how, well, I don't quite understand it myself." He turned and pointed off into the distance. "As the crow flies..." He put Bessie into gear and maneuvered out of the car park.**

**"But how can you be so sure without knowing how?" Jo was not about to let the subject drop. The Doctor certainly hadn't been himself lately, and she wasn't all together sure that he was thinking clearly. **

**She almost wished she hadn't asked as she saw the Doctor slip into lecture mode. "I have a theory, but it doesn't quite check out. Being mildly telepathic myself, I am able to follow psychic impulses through either intense concentration or lowered psychic defenses." He glanced at Jo, who blinked uncomprehendingly. "I have to be trying really hard, or I have to have my psychic defenses weakened through illness or fatigue," he tried to clarify.**

**"It's easier because you're sick, right?"**

**"Top of the class, Jo. And like most forms of communication, it should get easier to follow the closer we get."**

**"So what doesn't check out?" Jo asked.**

**"It's too strong. The psychic impulse, I mean."**

**"But you said-"**

**"I know what I said, Jo. It's possible that this girl is just unusual, but..."**

**"But you think she might be an alien," Jo concluded. "But why didn't you tell the Brigadier? He might've listened to you if you'd explained."**

**The Doctor snorted, "And what? Have him charge in, guns blazing?" Jo felt him lean harder on the gas pedal. "If this is just a missing child, the poor girl would be traumatized for life!"**

**Jo shook her head, "Now, really, Doctor. You don't honestly think the Brigadier would pull a gun on a six year old girl, do you?"**

**The two rode in silence for nearly an hour before the Doctor suddenly pulled Bessie over into the gravel driveway of a field. **

**"You think she's out there?" Jo asked doubtfully.**

**"Nope," the Doctor replied matter-of-factually pointing to the adjacent woods. "She's in there. We'll have to walk from here." He reached into the seat behind him and pulled out an army pack. "Food, water, and that blanket," he explained slinging it over his shoulder. "She likely hasn't had anything to eat or drink, and while it has been mild for January, it's far from warm. She's spent the night outside."**

**Jo trotted to catch up to him as he strode purposefully through the trees. "I hadn't even thought about that! What if she didn't make it through the night!"**

**The Doctor put a comforting hand on her shoulder, "Not to worry, my dear. If she's not alive, then what am I following?" He smiled as he felt her relax somewhat. "I think it'll be a bit of a walk yet."**

**He passed the time by pointing out trees and shrubs while Jo tried her best to look interested. Halfway through a lecture on the silver birch, the Doctor turned to her. "We're very close. She could probably hear us if we called for her."**

**Jo was apprehensive. If they were close enough to be heard, but she didn't answer, what would that mean?**

**"Ah-CHOO!"**

**"What was that?"**

**"That was me!"**

**Jo shook her head frantically, "No, not you! Listen!"**

**The Doctor could hear it, too. A rusting in the bushes accompanied by a low growl. It was coming closer. He stepped in front of Jo, instinctively shielding her from whatever creature was lurking in the shrubbery.**

**"Chaaaaaaaarrllieeeeee!"**

**Upon hearing its name, the beast raised its head, turning toward the summons. It was a large dog! A mutt, it seemed, to the Doctor. A very handsome one, at that! It had the slim face of a golden retriever and the short hair of a yellow Labrador. The dog gave the Doctor and Jo one last look before sprinting off with a wave of its bushy tail.**

**"That must be her dog," the Doctor reasoned. "Come on, Jo!" **

**They gave chase.**

**It wasn't far. The Doctor and Jo soon stumbled into a relative clearing where they were met once again with the growling Charlie. The Doctor noted that although his hair was mostly short, the dog had a line of longer hair that lead from the neck down to the tail which was standing on end like an absurd mo-hawk. **

**"Charlie, it's okay. He's a friend,"**

**As though understanding this new information through complete comprehension of English, the dog changed at once. No longer the menacing figure with his hair standing up, Charlie gave the Doctor a quick lick on the hand and an apologetic glance with his large brown eyes before looking at the ground submissively.**

**"Good boy," the Doctor scratched the dog behind the ears as he peered beyond him and saw a small figure curled up next to a tree. A silver birch, he noted, before impatiently waving away the unimportant information. She was wearing a purple knit coat that reached her knees over a blue checkered sundress that went just past her knees. A pair of scuffed, black, rubber rain boots nearly met the hem of her skirt.**

**Charlie pranced over to the girl and licked her face before curling up next to her. She in turn buried her face in his fur, her mid-length golden hair nearly blending into his coat. **

**"Adelaide?" Now that the dog would permit it, the Doctor knelt down beside her and took her hand. Her fingers were red from the cold, but she seemed all right. "I'm the Doctor, and this is Jo. We're not going to hurt you; we've come to find you."**

**Adelaide looked up with tired blue eyes. Her skin was light, and she had a pattern of freckles across her nose. "I know. You said you would come and find me." She smiled as though letting him in on a secret, "I know it's you because I recognize your hum."**

**The Doctor was taken aback by the peculiar statement, but set his inquiries aside for a better time. Instead, he pulled out a bottle of water and the army blanket from the pack. "Drink this, my dear," he coaxed as he wrapped the blanket around her. "Now let's get you out of here."**

**She was only a little more than three feet tall and weighed roughly forty pounds, so the Doctor had no trouble carrying her cradled in his arms. Charlie whined slightly as he picked her up**

**"It's all right, Charlie. Thank you. You kept me safe."**

**Jo got the feeling that this was something Adelaide often said to Charlie to reassure him that he had done a good job. While she had been frightened of him initially, she now found him to be very sweet. "You kept her warm, didn't you, boy," Jo patted him on the head as they followed the Doctor through the woods.**

**The Doctor looked over his shoulder at them and smiled, "Yes, you're very lucky to have such a devoted dog; he may well have saved your life!" **

**"He's my best friend," Adelaide murmured, taking a drink of water. "I think he's thirsty, too."**

**"Don't worry, we passed a spring on the way here, didn't we, Doctor?" Jo chimed in.**

**He nodded. "It's coming up soon. We'll take a break there where he can get a drink."**

**As promised, the group soon came to a small spring where clear, cool water gurgled along like a tiny river in its own miniature channel. **

**"Here we are," the Doctor announced. Charlie pricked up his ears as the sound of trickling water and bounded forward to gratefully lap it up. The Doctor set Adelaide down on her feet next to her thirsty companion and took one of her hands. "You seem warmer, anyway. How do you feel?"**

**The small girl looked bashful, "A little hungry," she confessed.**

**The Doctor furrowed his brow, "Oh, of course. How thoughtless of me. Jo?" Jo brought the traveling bag over and handed it to him. "We have some granola bars for now. We'll get you something proper to eat once we get back."**

**She took the granola bar that he offered, "Does it have chocolate in it?" she asked as she struggled with the package.**

**The Doctor held out his hand in an offer to open it for her, "No, it's peanut butter. Is that all right?" he asked as he broke the seal.**

**"That's perfect," she assured him. Taking back the now unwrapped bar, she divided it in half and gave one portion to Charlie. "Dad says chocolate's not good for dogs," she explained, patting her friend on the head as he gobbled down the ration. **

**The Doctor opened another bar and gave it to Adelaide. "You don't have to do that; there are plenty." He turned to his assistant, "Would you like one, Jo?"**

**Jo accepted a bar and sat down next to Adelaide, who was finishing her second bar. Charlie came over and put his head in Jo's lap. "Hello, Charlie," she grinned brightly, but the dog merely shifted his head slightly and gave a small whine. Adelaide clicked her tongue three times and Charlie perked up his ears and trotted happily to his small companion. **

**"Can you sit?" The dog happily complied as Adelaide carefully placed the last piece of her granola bar on the end of his nose. "Wait for it..." Charlie stood perfectly still, staring intently at his treat until... "Get it!" In one deft movement, he tipped his head and caught the bit of granola in his mouth. "Good boy!"**

**The Doctor chuckled while Jo clapped her hands. "That's pretty good!"**

**"Does he know any more tricks, Addie- er, Adelaide?" Jo looked sheepish, "Sorry."**

**"I like the nickname 'Addie'," the Doctor mused aloud, stretching out his long legs and lounging against a large rock as he absentmindedly whittled the bark off a discarded twig. "Do you mind if we call you 'Addie'?"**

**The child tilted her head as if to consider the proposition. "Yes, okay. You can call me 'Addie'." She scratched Charlie behind the ears. "He does lots of tricks if I ask him to. He sits, lays down, stays, fetches, stands up... uh..."**

**"Rolls over?" the Doctor prompted.**

**Addie shook her head, "Nope. He doesn't want to do that one."**

**Jo smiled, "Oh, that's okay. I'm sure you can teach him eventually."**

**Addie's demeanor suddenly changed. Her shoulders seemed to droop, and she clutched at Charlie's fur. **

**"No, I can't."**

**Her voice wavered as her lower lip trembled. Charlie whimpered sympathetically as a tear slid down her cheek.**

**The Doctor looked up from his twig, frowning in concern.**

**"Why not?" Jo asked, bewildered by the sudden depression. She reached out and placed her hand on the child's shoulder comfortingly. "What's wrong?"**

**"Charlie," she whimpered, her voice strained as she tried not to sob outright. "When we get home, they're gonna take Charlie away."**

**"But why will they take Charlie away?" Jo tried to make her voice gentle, the way primary school teachers spoke to their young students.**

**Addie had taken to clinging to Charlie as though afraid he might suddenly disappear. She wouldn't look at Jo or the Doctor and was trying, unsuccessfully, to hide her tears. Without preamble, she began to explain. **

**"Grandpa told my mum and dad that it's not good for me to spend all my time with a dog and not make friends with kids my own age." She took a shuddering breath. "He said that if they took Charlie away, then I would have to make friends."**

**Jo frowned; that didn't seem entirely reasonable.**

**"Mum and Dad are really worried that I'm not friends with any of the kids at school. James says it's because there's something wrong with me."**

**"James?" the Doctor inquired.**

**"He's my brother. He must be right because they keep taking me to doctors who try to make me better, but it doesn't help." Addie stroked Charlie's fur, an activity that seemed to calm her. "I know that they just want to help me. Sometimes... Sometimes when James is playing with his friends, and Mum sees me by myself, I feel her get really sad." **

**The Doctor leaned forward intently, "You feel her sadness?"**

**"What does it feel like?" Jo asked. The Doctor cringed inwardly. Of course, he was wondering the same thing, but he was also acutely aware of the emotional stress such a question was putting on the already exhausted child. Just as he'd feared, the poor girl buried her head in her hands, visibly trembling.**

**He cleared his throat uncomfortably, "We... We're losing daylight; we had best be going." He tossed his twig aside only to have it dutifully retrieved by the eager mutt. The Doctor smiled despite himself, but it was short-lived as Addie's mood didn't improve. He sighed. If there was one thing that would always tug at his hearts, it was crying children. **

**The Doctor gave Jo a meaningful look, handing her the twig and tilting his head toward an attentive Charlie. She nodded in understanding, "Come on, Charlie, fetch!"**

**As Jo went off to entertain their furry charge, the Doctor knelt down next to Addie. He waited patiently for the child to take her head out of her hands before coughing politely to catch her attention. She started a bit, apparently having forgotten she was not alone. Sniffling slightly, she met his eyes for a moment before glancing back down at her boots.**

**"I'm sorry." She sniffled again.**

**"You've nothing to be sorry for."**

**Addie responded with another sniffle. The Doctor shook his head, "Oh, dear. That won't do at all." She glanced at him apprehensively, unsure of what he meant. "Have you got a hanky?" he asked her gently. **

**"I..."**

**He smiled lightly, "Not to worry, my dear. I've got a spare you can have." The Doctor made a show of checking his pockets. "Now where did I..." He paused theatrically, "Ah, yes, now I remember." Leaning over, he reached behind her ear and pulled out a blue linen handkerchief. "Silly place to leave it, I suppose."**

**Addie giggled as the Doctor presented her with the handkerchief. "There, now, that's yours. Dry your eyes; blow your nose. There's a good girl." She complied, and the Doctor stood up to stretch his legs. **

**After shoving the handkerchief into her coat pocket, Addie stood up as well. The Doctor beamed down at her, offering his hand, "Let's get going, shall we?"**

**The sun was getting low in the sky when Jo and the Doctor finally stepped out of the woods with Charlie hot on their heels. Addie had fallen asleep in the Doctor's arms soon after it had become obvious she was too tired to walk, and he was trying his best not to wake her as he gently loosened her grip on his frilled shirt.**

**Jo opened the door to the back and the Doctor set his bundle down in the middle of the seats. "There's enough room for you on the other side, Jo. Stay back here with her, would you?" He looked up to see that Jo was already climbing in next her their young charge. "Right," he patted the his side of the back seat, "Come on, boy, in you get."**

**Charlie looked up at the Doctor uncertainly before sticking his nose in through the door. It was obvious that the dog was not usually allowed to ride in vehicles. Conflicted between following his master and a possible scolding, he whined pitifully.**

**Addie stirred slightly at the sound, "It's all right, Charlie. Come here." she murmured groggily. **

**At this reassurance, Charlie stepped gingerly into the roadster, curling up protectively next to his friend. **

**The drive was quiet, and as the Doctor pulled Bessie into the U.N.I.T. Parking lot, he glanced back to see that his passengers had all fallen asleep. The stars had already found their way out into the cloudless sky, and he sat for a moment, taking in the serene ambiance before climbing out of the car.**

**Jo woke as the Doctor gave her a gentle shake, "It's late, my dear. Would you like one of the soldiers to drive you home?" he asked. Jo shook her head and insisted she was fine before she glanced at the child sleeping next to her.**

**"Home? Doctor, you forgot to bring her home!"**

**The Doctor brought a finger to his lips, shaking his head. "Don't worry about that, I'll handle it. Just go home and get some sleep." Jo opened her mouth to protest, but the Doctor held up a hand to quiet her. "Go home and get some sleep," he repeated in a whisper. Too tired to argue, Jo nodded and climbed into her car, which was parked a space over, and drove off.**

**Charlie lifted his head as the Doctor opened the door and hopped out with little coaxing. He sniffed the ground experimentally before stopping suddenly. His mo-hawk stood up and he growled in the direction of a torchlight. **

**"Doctor?" It was Sergeant Benton, the moonlight casting an eerie glow on his face as he stepped into view.**

**Charlie's growl increased in pitch and he stepped deliberately in front of the Doctor. "No, Sergeant!" the Doctor hissed as the young soldier instinctively touched his sidearm. "It's all right, Charlie; he's a friend."**

**It was the same transformation; the menacing mutt became friendly. He trotted up to give Benton an apologetic lick on the hand before prancing back to the Doctor's side.**

**"New dog?" Benton asked uncertainly.**

**"After a fashion," the Doctor answered, patting the dog on the head. "I don't suppose you could do me a favor, old chap, and take him for the night?"**

**Benton hesitated. **

**"He won't bite you, Sergeant," the Doctor said patiently.**

**"One night? Well, I don't know, Doctor..." **

**"Oh, he'll like you; he seems to like anyone friendly. His name's Charlie. Go on. Call him."**

**Sergeant Benton cleared his throat, "Here, boy," he called feebly, snapping his fingers. Charlie obeyed immediately, bounding over to the soldier, enthusiastically waving his tail. A broad smile slowly spread across the sergeant's face as he as he knelt down to pet the mutt. "He didn't half come, did he? Oh, all right, one night."**

**"Thank you, Sergeant." The Doctor put a finger to his lips before reaching into the the back seat of Bessie and carefully extracting his young charge. Charlie was at his side immediately, whining at his feet. "No, Charlie, go with Sergeant Benton," he coaxed.**

**"What's that, Doc?" Benton leaned forward curiously. **

**"Quiet, Sergeant," the Doctor insisted, but it was already too late. Addie stirred and rubbed her eyes.**

**"Charlie? Where are you?"**

**The Doctor lowered her down to stand on her feet. "He's right here, my dear. Our friend Sergeant Benton was just going to take him to-"**

**"No!" The child threw her arms around the dog's neck. "You can't take him away!" she cried.**

**Thoroughly bewildered, Benton sputtered uselessly. The Doctor, however, knelt down and took one of Addie's shaking hands. "He's not taking him for good, my dear. Just for tonight; you'll see him tomorrow. He can't come where we're going."**

**"Why not?" Addie's lip trembled, "Where are we?"**

**"We need to make sure that you're all right before we bring you home," The Doctor explained.**

**"A hospital?"**

**The Doctor considered for a moment, "There is something like a hospital inside, yes."**

**"Oh. Dogs aren't allowed in hospitals." Crestfallen, Addie hugged Charlie and gave him a kiss on the nose. "You need to go with him, Charlie," she told her friend as she led him to the soldier.**

**Benton knelt down, solemnly taking off his beret. "I'll take good care of him, miss," he assured her, his voice catching in his throat. "I'll have him here b-bright and early tomorrow. **

**"For goodness sakes, it's only a night!" The Doctor protested reasonably, though the scene was quite touching.**

**Blinking rapidly, Benton stood up and led Charlie away. The Doctor took Addie's hand again, giving it a reassuring squeeze as the child watched her best friend disappear into the darkness.**

**Apart from the on-duty soldier standing guard, who could no longer be phased by anything that went on involving the Doctor, the Time Lord leading a small child by the hand were received without question. This was much to the Doctor's liking; there were certainly times when drawing little attention to oneself was advantageous, and this was one of those times. He was quite sure that the Brigadier would not approve of what he was doing and would probably have an aneurism if he found out.**

**WHEN he found out, the Doctor amended.**

**The two finally rounded the corner to the hall of the Doctor's laboratory, and by this point their pace had slowed to a crawl as Addie shuffled along, rubbing her eyes sleepily. The Doctor sighed inwardly. As eager as he was to start running tests, he knew he couldn't allow himself to do so until Addie had gotten some more rest.**

**"I'll be just a moment, my dear," the Doctor promised as he disappeared inside the blue police box. He reemerged moments later with a pillow and blanket taken from the closest bedroom. To his concern, he found that Addie had disappeared. Frowning, the Doctor carried the items to the battered sofa in the corner of the lab where he found his young charge. It looked as though she had fallen asleep while trying to climb onto the cushions.**

**Chuckling lightly, the Doctor set about to tuck her in properly. He gently eased off her coat and removed her boots. Having been so easily awoken earlier, the Doctor wondered at her lack of response as he draped the blanket over her. He placed a hand in front of her mouth and felt her slow, regular breathing. **

**No. Just tired.**

**He switched off the lights**

**In his office, the Brigadier jumped slightly as the telephone on his desk came to life. He stole a quick glance at the clock, which read nearly midnight, and picked up the receiver. "Lethbridge-Stewart."**

**"Doctor's back, sir." It was the young duty sergeant.**

**"Ah, yes. Did he send Miss Grant home?" The Brigadier was well aware of the Doctor's tendency to forget that humans needed sleep, and often times the Brigadier had to dismiss her for the night personally.**

**"Well, there was someone with him, sir, but it wasn't Miss Grant."**

**The Brigadier snapped to attention in his chair. "Who?"**

**Sensing the slight edge in the voice of his commanding officer, the sergeant became uneasy. "Well, sir..." he stammered, suddenly realizing his mistake, "He had a little girl with him. I'm sorry, sir, I should have asked, but it was the Doctor and I didn't think anyth-"**

**The Brigadier slammed the receiver back into its cradle. "What IS the man playing at?"**

**Tropical storm Brigadier exploded through the office door.**

**Before he could reach the Doctor's laboratory, Lethbridge-Stewart found himself automatically calming down. It was somewhat irritating that he could rarely manage to make it all the way to his scientific adviser before losing his passion to storm in and give the man a proper verbal throttling. The Brigadier straightened his posture. Never the less, the Doctor needed a stern talking to. Perhaps taking in stray civilian children was standard procedure on his planet, but here it was kidnapping.**

**He knocked smartly on the door before before deciding that he should be more commanding and entered without invitation. The room was dark, save for the light glowing through the open door of the Doctor's police box out of which the Doctor himself was stepping, his white hair looking iridescent. **

**As expected, the Doctor glowered at the intrusion. Unexpectedly, however, the Doctor didn't give a retort, but merely bungled the Brigadier out into the hall. Stunned, Lethbridge-Stewart didn't protest until the Doctor had carefully closed the door behind them.**

**"****What the devil-!"**

**"****Brigadier," the Doctor cut in, "I need your help."**

**"****What?"**

**"****I need records for Adelaide Redbarrow. Medical at least; School if you can manage-"**

**"****Doctor-"**

**"****Yes," the Doctor sighed impatiently, "I have her with me. She's asleep, or at least she was before you barged in with your heavy handed military..." He swallowed the rest of the insult with some difficulty.**

**"****Doctor, I can't allow this! It's kidnapping! You can't just take ordinary civilians from their families and bring them to a top secret military establishment!" The Brigadier frowned coldly. He knew the Doctor wasn't really so careless; there had to be an explanation, but what could possibly...?**

**The Doctor had that knowing smile of his. "My dear Brigadier, I don't believe our young friend is all she seems."**

**"****Oh?" The Brigadier raised a patient eyebrow, "What makes you say that?" he asked skeptically.**

**The smile became a thoughtful frown, "It's too difficult to explain, but I'm running a DNA sample to see if she is of terrestrial origin."**

**"****She looked human, though."**

**The Doctor gave a patronizing sigh, "You of all people should know that doesn't count for much. Though, I must admit, she doesn't have a pesky second heart to give her away; I checked."**

**The Brigadier rocked on his heels, turning the information in his mind, what he could understand, anyhow. "You thought she was one of your lot, then?" The idea that the Doctor was once a child strangely never crossed his mind. When the Doctor didn't answer, the Brigadier continued his protests. "Why do you want records if you have her here already?"**

**"****Because something isn't right," the Doctor stated evasively. "Her psychic pulses are too strong for a human, but maybe they can be explained."**

**The soldier sighed, his face impassive. "All right, Doctor. If we get you these medical records, you can send her home?"**

**Now the Doctor sighed, as though the Brigadier hadn't been listening to a word he said, "If I'm right, and I usually am, she could be in danger."**

**"****But surely-"**

**"****That's why I need those records, there's a good chap." The Doctor clapped him on the shoulder before ducking back into the lab, locking the door behind him and leaving UNIT's commanding officer seething in the corridor.**

**"****Absolutely typical."**

**"****Good morning, Doctor," Jo sang as she entered the lab. The Doctor quickly looked up from his work and placed a finger to his lips, but gave her a small wave with his other hand. She gave him a quizzical look, "Are you still not feeling well, Doctor?"**

**The Doctor frowned and said, "Hmm? Oh, no, I'm quite well, thank you, my dear. Ah, no matter, she's awake."**

**Jo turned to the movement at the corner of the lab. Addie was rubbing her eyes drowsily.**

**"****Where am I?"**

**The Doctor came and sat next to the child on the sofa. "Don't you remember?" he asked.**

**Addie closed her eyes for a moment, as though concentrating to retrieve the memories of the night before. She said with a smile, "Oh, yes. You're the Doctor."**

**The Doctor grinned. "Yes, that's right. Do you remember my assistant, Jo?" Jo sat next to the Doctor and smiled warmly.**

**Addie looked confused and disoriented for a moment, and the Doctor reacted just in time to catch her before she fell off the couch. "Steady on, my dear," he whispered soothingly, coaxing her to lie back down. **

**"****What happened?" Jo asked worriedly.**

**The Doctor placed a hand on the child's forehead.**

**"****Am I ill?" Addie whimpered. He felt her shiver, obviously spooked by the sudden dizzy spell. **

**"****Hmm. No fever. In fact, you seem a touch parky." He pulled the blanket back over her. "You're probably just weak; you haven't been eating properly."**

**"****Well, neither of you have had breakfast, then." Jo stood up. "I'll pop down to the canteen."**

**"****Best get her something with protein." The Doctor touched her forehead again. "And some hot, sweet tea."**

**As Jo left, Addie sat up carefully. "Could being hungry really make me dizzy?"**

**The Doctor was beginning to wonder if she had ever been severely ill. "You really are frightened, aren't you?" **

**"****When is Charlie gonna get here?"**

**The Doctor smiled. "Sergeant Benton took him out for a run; they'll be back soon." **

**The small girl looked dejected and curled up, hugging her knees self-protectively. "Okay."**

**Suddenly remembering, the Doctor placed a hand on her shoulder. "What did you mean yesterday when you said that you recognized my, er, 'hum'?"**

**Chin on her knees, Addie tilted her head to look up at him. "I felt it in the woods when Charlie and I were lost."**

**"****Felt it? How do you mean?"**

**"****In my head... sort of..." She struggled to explain. "Behind my eyes."**

**"****Really? How extraordinary."**

**Addie fidgeted uncomfortably. "I'm weird, aren't I?"**

**The Doctor chuckled. "You humans and your desire to be ordinary. Why don't you aspire to be clever? Comical? Knowledgeable? Memorable? Instead, you want to be like everyone else. What a waste, don't you think?"**

**There was a cordial knock on the door, and the Doctor turned around to see Sergeant Benton stride in with a very excited Charlie. **

**"****Morning, Sergeant," the Doctor greeted.**

**"****Good morning, Doctor, Miss." The sergeant returned politely. The dog quickly set about investigating his surroundings until he caught sight of a familiar face.**

**"****Charlie!" Addie wriggled out from under the blanket and bounded off the sofa to embrace the mutt. Charlie licked her face enthusiastically, making her giggle. The Doctor smiled broadly at the reunion. He caught Sergeant Benton leaving a small stack of documents on a lab table and silently excusing himself from the room.**

**"****Hand me that file, would you, Jo?" The Doctor held out his hand without looking up from the report he was rapidly skimming. Jo retrieved the manilla envelope and positioned it among the other documents that encircled the Doctor's untouched cup of tea, which had long since gone cold. **

**"****Doctor?"**

**"****Hmm? Yes?"**

**"****What exactly are you looking for in all this stuff?"**

**The Doctor looked up at Jo. His gaze shifted to his outstretched hand that had failed to receive the folder. He frowned until his eyes landed on the coveted envelope in front of him. "Never mind, Jo, I've found it." He said absently, tipping the contents of the envelope onto the table and spreading it out so he could view it all at once.**

**Jo sighed. "I mean, you've been at this for almost an hour. It never takes you this long to read up on things, so you must be searching for something."**

**He was silent for a few moments before he leaned back in his chair. His rubbed his eyes wearily, looking uncharacteristically defeated. "She's human, Jo. I can't find any evidence to the contrary. Her medical records indicate human blood, human organs, human everything."**

**"****There certainly are a lot of records here for a six-year-old," Jo mused aloud.**

**The Doctor leafed through a small folder of papers. "A good share of them are psychological evaluations and other such paraphernalia kept on file." He grimaced with distaste. "Most of it is codswallop. Aside from that, there is everything we could have asked for, really." He held up a particular document and an x-ray. "Starting with her regular, human birth at six pounds three ounces and going up to her completely human, unbroken right clavicle almost three months ago."**

**Jo glanced across the lab to where Addie was sprawled out on the floor. After some searching, Jo had found some crayons and paper for her, and she was contentedly occupied. Charlie lounged next to her.**

**"****Okay, so she's human. Why does that upset you? I mean, not everyone who is a bit odd is an alien."**

**Before the Doctor could reply, the Brigadier strode in. Jo noticed that the Doctor seemed to unconsciously shift his demeanor from weary to slightly aloof. How often did the Doctor have to admit he'd made a mistake?**

**Upon the entrance of the Brigadier, Charlie leaped to his feet with a sharp growl that made Addie look up apprehensively. **

**"****It's all right, Charlie, he's a friend." The Doctor snapped his fingers to summon the mutt to his side. "Good boy," he crooned, scratching him behind the ears. Charlie's head drooped apologetically, and he licked the Doctor's hand before trotting back to his companion.**

**As if nothing had happened, Lethbridge-Stewart stood stiffly with a mild expression on his face. "Good morning, Doctor, Miss Grant. Now, about this..." He trailed off as he caught sight of a pair of wide, blue eyes staring at him from across the room. UNIT's Commanding Officer cleared his throat, now looking unusually uncomfortable. It was obvious he wasn't certain that this matter should be discussed in front of the child. "Doctor, I would like to speak with you in my office," he amended.**

**"****Certainly, Brigadier," the Doctor replied smoothly. No use in giving up the game until the very end. Jo helped him to gather up the reports, and the two of them locked eyes for a moment. The Doctor gave her a brief smile before accompanying the Brigadier to this office.**

**In his office, the Brigadier got straight to the point. It made his insides squirm to think of the family losing hope of finding Adelaide Redbarrow when she was quite safe. "Doctor, this has gone on long enough! UNIT cannot harbor civilians! This is not a daycare. I want her out; more specifically, I want her back home where she belongs!"**

**For a moment, the Brigadier felt certain that the Doctor would retaliate, going into some tirade about the fate of humanity being in jeopardy. The worst of it would be that the Brigadier would have no choice but to trust the Doctor's judgments. The man had an infuriating habit of being right about these matters.**

**"****You're absolutely right, Brigadier," the Doctor said instead, standing up from his chair to pace the floor. The Commanding Officer was half way through a retort before he actually took stock of what the Doctor had said.**

**"****Beg your pardon?"**

**"****But I'm afraid we've created rather a new problem," the Doctor continued to speak, ignoring the Brigadier's confusion.**

**"****We?" the Brigadier whispered indignantly in his head, but nodded at the Doctor's statement. "Probably. We shall have to devise a method of returning her home without exposing UNIT's involvement."**

**The Doctor, who had been reaching for the door, stopped and turned to face his colleague. "My dear fellow. I was talking about the crayons currently strewn about my lab." His cheeky grin was cut off as the telephone on the desk began to ring.**

**Benton had showed up again to make sure that everything was still all right in the lab (though Jo felt certain that what he really wanted was to visit Charlie). "What did the Doc want all this for anyway?" he asked after he had finished petting the dog and had started to help Jo arrange the papers into neat stacks. "Are you all right, miss?"**

**Jo nearly answered before she realized that the last question had not been directed toward her. As they had been talking, Addie had begun to cough. Lightly at first, but with increasing severity. Jo felt a leap of panic in her stomach. "Is she choking?"**

**"****She couldn't cough if she was choking. Call the MO; something's wrong!" Benton didn't wait for Jo to act on the command. He scooped up the telephone receiver himself and phoned the Medical Officer. **

**No sooner had the receiver hit the cradle before Jo snatched it up and dialed the Brigadier's office. **

**The MO arrived with remarkable speed, bag in hand and a stethoscope swinging madly around his neck. "Out of the way! OUT OF THE WAY!" he cried, self-importantly nudging the sergeant aside. He knelt beside Addie, who was now coughing and gasping desperately, and pressed the stethoscope to her chest. "Her heart's going crazy. I need to shock it to set it right." His voice was sterile and calculating as he pulled out a needle to administer fluids intravenously. **

**"****Not that, you nitwit!" Suddenly, a strong arm forced the Medical Officer out of the way. In a blur of velvet, the Doctor snatched the patient right out from under him.**

**The Doctor pressed the very center of the child's back and applied a firm pressure below her left ear.**

**"****How DARE you-? What ARE you-?" the MO sputtered. The Doctor shot him a glance that shut him up, though his eyes continued to bug out of his head as though a furious pressure was building in his skull. Whether this was due to rage or incredulity as the treatment began to work was difficult to say.**

**As the coughing subsided completely, the Doctor stopped applying pressure and allowed the girl to crawl into his lap. "It's all right, now, my dear," he murmured soothingly.**

**"****It hurts!" Addie whimpered. "Right here." She clutched the right side of her chest.**

**The Medical Officer snarled, "She probably ruptured a lung because-!" He was cut off as the Doctor reached over and yanked the stethoscope away.**

**"****Who called this idiot in here?" the Doctor growled, putting the leads in his hears. He placed the scope on her back over her right lung. Nobody moved as he listened intently, his face becoming more and more puzzled. "That can't be right, surely..."**

**He switched to the front, placing the scope on the right side of her chest. "Incredible."**

**"****We must get her into treatment for her heart," the medic urged. "She-"**

**"****Those were not heart palpitations! Brigadier, get this nitwit out of here!" **

**The Brigadier ordered a confused Benton to show the MO out of the lab. "Shouldn't we get her to hospital, he asked after he had safely gone.**

**The Doctor shook his head. "They wouldn't know what to do with her in hospital, Brigadier, any more than they would know what to do with me. There's nothing wrong with her heart."**

**"****Well, then, what is wrong?" the Brigadier demanded.**

**The Doctor rubbed the back of his neck, "The problem isn't her heart, rather the fact that she has one too many."**

**"****Two hearts," Jo breathed. "But- but, Doctor, you said that-"**

**"****Yes, Doctor," the Brigadier cut in, "you just finished informing me that Miss Redbarrow was in fact human."**

**Jo was incredulous. "But humans can't have two hearts!"**

**"****Well, of course they can, Jo. George Lippert, for one, though he also had three legs. But that's not the case here. No. Humans with two hearts are born with two hearts. This right heart definitely wasn't there before."**

**The Brigadier pinched his nose in frustration, finding himself, once again, out of his depth of understanding. "I'm not following you, Doctor. What the devil is going on!"**

**"****I haven't the faintest idea."**

**"****Then call me when you have." He turned to Jo. "See to it that he does." And with that, the Brigadier made for the door. He didn't have time for puzzles that refused to be solved; that was the Doctor's job.**

**The Doctor sat wrapping wire around a metal bolt; a task meant merely to occupy his hands. He always thought more clearly when his hands were busy. He had sent Jo on a supply hunt, though he was quite certain she knew that he simply wanted her out of the room for a while. It pained him to make her feel unwanted, but it had been necessary. He needed answers, and the less company, the better.**

**He set down his bit of electronics and glanced over to the more child-friendly area of the laboratory where Addie was scribbling away with a forest green crayon. It was something to occupy her time while Sergeant Benton took Charlie out for some exercise. All seemed peaceful enough. The Doctor stood up from his chair and made his way casually to the sofa.**

**"****Feeling better, my dear?" he asked.**

**Addie nodded hesitantly, not pausing her work.**

**The Doctor leaned over to look at her paper. "What are you drawing?" **

**She covered it with her hands. "Just something. It's not very good." She looked bashful and turned over her small stack of drawings. Unperturbed, the Doctor gave her his most winning smile, to which, the child eventually gave in and handed over the papers.**

**A promising sign. He needed her to open up to him.**

**The first, predictably, was a drawing of Charlie. The second was of him and Jo, which he had to admit, was quite good. Next was a drawing of Sergeant Benton throwing a blue ball to Charlie.**

**It was the fourth picture that made him laugh out loud.**

**"****Good grief! It's Lethbridge-Stewart! You've captured his likeness quite admirably."**

**The Doctor sat on the sofa, and Addie crawled up next to him. "I didn't know that was his name." She fiddled with the crayon she still held. "I don't think he likes me."**

**He was caught off guard by her frankness, but recovered quickly. "Oh? What makes you think that?"**

**She wouldn't look at him. "He's always upset when he sees me. Did I do something wrong?"**

**Shaking his head, the Doctor set down the stack of drawings. "He's just confused. In fact, we all are." He sighed. "Adelaide, is there something I should know about?"**

**She responded to the use of her proper name with bewilderment. "What?"**

**The Doctor tried again, "It's all right; you're safe here. If you're hiding something, I need to know so I can help you." He tried his best to swallow his growing anxiety, but he could tell by her features that she was picking it up despite his efforts.**

**"****You mean like when I couldn't breathe?" She brought her hands to her throat. "Will that happen again?" **

**The Doctor could feel her rising panic lapping at the edges of his subconscious, and he placed a gentle hand on her back to stop her working herself up into a fit. "You mean what happened today has never happened to you before? Is that right?"**

**Addie nodded, and she looked up at him with shining blue eyes. "I think something's wrong with me inside now. Can you fix it?"**

**The Doctor put an arm around her and let her head rest against his side. By now, it was obvious that she was not hiding anything, but what did that mean? He couldn't help but feel that this would all make sense if the Time Lords hadn't taken some of his memories.**

**"****Doctor?"**

**He looked down. "Yes?"**

**"****I'm scared."**

**He stroked her blonde hair as she drifted off to sleep. "Don't cry, Susan. I'm right here."**

**Whenever UNIT's activities (or lack there of) permitted, Jo looked forward to the hour long break for lunch. As exciting as it was to be a sort of super-spy, it was relaxing to spend an hour or so chatting with Mike and Sergeant Benton over a cup of tea or taking a walk around the grounds of UNIT HQ. Sometimes, when she could convince the Doctor to take a break from his tinkering, he would come with her.**

**"****No, I don't think so, Jo. Not today."**

**Jo always disregarded his initial lack of interest as it was normal for the Doctor to disagree at first.**

**"****Look, why don't you take Addie and Charlie with you? I'm sure they'd like to get out and stretch their legs after being cooped up in here all of yesterday."**

**Jo nodded. "They're already coming. Addie's finding her shoes and coat. But we want you to come with us, don't we, Addie?"**

**Addie peaked out from behind the sofa holding a rubber boot in her hand. She nodded enthusiastically, her wild blond hair swishing in front of her face. She unceremoniously thrust her foot into the boot and clomped childishly over to Jo and took her hand. It was amusingly obvious that she had buttoned her coat without assistance.**

**"****See?" Jo continued. "Oh, come on, Doctor. We haven't gone for ages since you've been ill." She suddenly put her hand to her mouth. "Oh, I see. Are you still feeling a bit weak?"**

**The Doctor wasn't altogether certain whether Jo was speaking out of genuine concern or simply baiting him. Either way, he indignantly stood and took his cloak from the coat rack. "I assure you, my dear, that I am in perfect health."**

**Jo and Addie shared a glance, and Addie giggled.**

**"****Now don't you start!" he chided gently. The Doctor knelt down to button her coat properly. "It would seem you haven't had any trouble with this, then," he continued, checking the small device pinned to the collar of her shirt. It was a sort of hearts monitor that he had rigged up to keep tabs on the strange happenings of Addie's circulatory system. If any further abnormalities were detected, the tiny machine would send a signal to an, admittedly anachronistic, pager in the Doctor's pocket. Thankfully, there had been no more incidents since the day before.**

**On the other hand. unfortunately, the Doctor was also no closer to understanding what was happening. Having two hearts was nothing new to him, but it certainly was for her. The x-ray and his initial exam both ruled out the prior existence of a binary cardiovascular system. To his knowledge, no species could simply grow a new heart in such a short amount of time. Where could she have come from?**

**It was no use asking her; she obviously didn't know. **

**She wouldn't even be old enough to look into the Untempered Schism. He remembered when Susan-**

**Why was he comparing her to a Gallifreyan? She couldn't possibly be Gallifreyan. Could he be missing home? Certainly not!**

**"****Doctor?"**

**Jo's voice pulled him out of his reverie, and he recovered by tweaking Addie's nose playfully before straightening up and taking the child's hand. "Shall we, my dear?" he asked as he offered Jo his arm.**

**"****Come on, boy!" Addie called to the sleeping mutt at the other end of the room. He leaped to attention with a sharp bark, and then hurried to follow his master out through the laboratory doors.**

**The crisp January wind blew gently through the trees as Jo and the Doctor walked across the grounds around UNIT. Jo glanced ahead to see Addie and Charlie several yards further along the route. They were running circles around each other with the perfect chemistry of two close friends. Her heart ached as she remembered what was to be their fate when they were finally returned home. **

**It reminded her of when her best friend moved away when she was a child. She had cried for days... She suddenly realized that her eyes were damp, and she sniffed inadvertently. **

**"****Are you all right, Jo?" **

**As surreptitiously as possible, Jo sniffed again. "Yes. It's... It's just something in my eye."**

**"****Oh?" the Doctor replied. "Let me take a look."**

**"****Never mind; it's gone now."**

**"****Well, if you're certain." Jo felt the Doctor's hand on her shoulder briefly.**

**When she had composed herself, she looked over at the Doctor. He was staring at the ground with a pensive expression on his face and his hands shoved deep in his pockets. Thinking, as usual.**

**"****Doctor?"**

**"****Hmm?"**

**"****You still think she's an alien, don't you."**

**The Doctor frowned at her. "Of course she's an alien, Jo. The question now is: From where?" His attention shifted forward. "Stay well clear of the water, Addie!" He warned as the little party was coming up to a small pond.**

**"****Yes, Doctor!" came the obedient reply from Addie. She showed little interest in the pond and instead sat down to rest a reasonable distance from the water's edge. Charlie settled down next to her with a twig in his teeth.**

**Satisfied, the Doctor stopped walking and turned his attention back to his assistant. "I need to get to the source. I need to speak to her mother."**

**"****What about her father? She lives with both. And maybe her brother knows something." Jo reasoned, but the Doctor shook his head.**

**"****Jo, you couldn't have possibly read those medical reports too closely to have missed the fact that Addie is not biologically related to her father or her brother, but she is Mrs. Redbarrow's biological daughter."**

**"****Oh." Jo bit her lip thoughtfully. "But why are they here pretending to be human?"**

**"****I think Addie truly believes she is human," the Doctor explained. "As for her mother, inter-species impersonation is more common than you realize, Jo, and for a variety of reasons." He began counting in his fingers. "Researching, crash landing, holidaying, invasion preparation-"**

**"****Exile?"**

**He made a face. "Earth isn't some sort of galactic prison, Jo."**

**She giggled. "Addie's much too sweet to be a criminal, anyway... Doctor? What's the matter?"**

**He wasn't listening. His eyes were staring past her, his brow creased in confusion. Before Jo could turn around and see for herself, the Doctor exclaimed, "Jehoshaphat!" and took off, cape billowing out behind him.**

**The Doctor sat down on the sofa and pulled on a pair of dry socks. There hadn't been time to take off his shoes before wading into the pond, and they were now lying in a soggy heap next to the Tardis along with his previous pair of socks, equally sodden. As he fitted his feet into a new pair of shoes, Jo came around with the tea.**

**"****Thank you, Jo."**

**"****How is she?" Jo asked urgently. After having helped Addie into a dry outfit from the Tardis wardrobe, the Doctor had sent Jo off to make tea while he took over caring for her. **

**He positioned the blanket more tightly around the child next to him. "She couldn't have been in the water more than fifteen seconds. A miserable ordeal, but she should be all right. What really worries me is why she did it." The Doctor took a cup of tea and offered it to Addie. "Here, drink this. It'll warm you right up." To his and Jo's surprise, the small girl grimaced and shook her head.**

**Jo sat down on the other end of the sofa. "I thought you liked tea; you've been drinking it since you got here." **

**Addie shook her head again and began to struggle against the blankets. The Doctor set down the tea. "Steady, my dear, you need to get warm." He reached out to calm her, but she had begun to thrash wildly about.**

**"****Where's Charlie! It's too hot! You're hurting me! You're hurting me!"**

**Bewildered, Jo tried to reason with her, "Charlie is with Sergeant Benton, remember?Look, we're not hurting you!"**

**"****She can't hear you, Jo. She's having some sort of fit. Help me hold her shoulders still." **

**The Doctor's voice was so calm that it took a moment for Jo to react. She did her best to pin Addie's shoulders while the Doctor pinched a nerve on the side of her neck until she stopped struggling.**

**"****What did you do?" Jo asked as the Doctor picked up Addie, taking as much of the blanket along as he could manage.**

**"****Pressure point; bit of something I learned on Venus. Knocked her out, but it will only last a few seconds until I can implement a more lasting solution," the Doctor explained over his shoulder as he carried Addie's unconscious form to the Tardis.**

**Jo trotted behind, ignoring the disorientation as she crossed the threshold into the Doctor's impossible police box. The Doctor walked past the console right through an open door that Jo could have sworn was not there earlier. **

**Then again, she had been to another planet in another time. What was impossible anymore?**

**She ignored this new confusion and met the Doctor in what looked like a small hospital chamber. He looked up from where he was hanging a bag of orange fluid to be administered by IV. "Jo, in that cupboard behind you, hand me a free needle, would you? It's about three quarters of an inch. Hurry!"**

**Jo brought the needle, and the Doctor began to administer the fluid just as Addie was beginning to stir. She let out a helpless sob, and the Doctor stroked her bangs back, crooning a few bars of what sounded like a lullaby. **

_**It will be alright, my darling**_

_**Sleep, my darling child**_

_**Twin suns will greet you with a warm embrace**_

**In moments, Addie was silent. The Doctor let out a sigh. Reaching down, he brushed the tears from her cheeks. **

**After a few moments of silence, Jo spoke quietly. "Doctor?"**

**"****Hmm?"**

**"****Has this happened before?"**

**The Doctor shook his head, rubbing his chin in thought. "I don't know what's wrong with her. I've never seen anything like it."**

**"****That wasn't what I meant." Jo thought to herself as she watched the Doctor tuck the small girl in with practiced ease.**


	2. Chapter 2

Jo sat on the sofa and watched the Doctor pace back and forth in front of her. Despite his insistence that he was fully recovered, Jo wasn't convinced. He still looked tired, and he was clearing his throat more than should have been necessary.

Not that any of that mattered, really. She could also see that he was determined to solve the mystery at hand, and blast if a slow recovery was going to deter him!

Jo leaned forward, knitting her fingers in an attempt to look business-like. "What's our next move, Doctor?"

The Doctor paused his pacing and looked down at her with a slight frown. "I've already told you, Jo. I've got to speak with Addie's mother. It's very likely that she's the only one who knows what's wrong with her daughter."

"But if you've already decided what we're going to do, then why aren't we doing it?"

The Doctor crossed his arms. "I can't just barge into their house and demand to know the planetary origin of Mrs. Redbarrow."

"Why not?" Jo stood up and began pacing, herself. "This is an emergency! Addie's getting worse, and you're worried about being tactful!"

Giving up on pacing, the Doctor dropped himself gracefully into the spot Jo had vacated on the sofa. He folded his hands and tapped his knuckles to his lips. "It's not that simple, Jo. I have no idea what race we're dealing with, and many races that go into hiding among other races become very disagreeable when found out. I could inadvertently start an inter-species war for which you humans would not be nearly prepared. There is also the possibility that Mrs. Redbarrow is not an alien."

"Doctor!" Jo groaned dramatically. "You said that you were certain that Addie was an alien, and now you're saying she isn't?"

"That's not what I'm saying at all," the Doctor stated calmly. "I'm merely bringing up the possibility that Addie is a member of a foster race." He leaned back into the sofa cushions. "She could be a Tenza, for instance." He looked up and noted the bemused expression on his assistant's countenance and sighed. "Look, Jo, did you know that the cuckoo bird lays it's eggs in the nests of other birds?"

Jo shook her head. "Don't the other birds notice?"

"Some do, but the cuckoos are evolving to lay eggs that more and more resemble the host's eggs. The host birds are tricked into raising the cuckoo as their own, often at the expense of their own offspring, which the young cuckoo often pushes out of the nest."

"That's horrible!" Jo cringed at the thought of baby birds plummeting to their doom. "Addie's not like that at all!"

"It's not a perfect metaphor," the Doctor admitted. "The Tenza are actually a very benign race. Their young hatch in space and find homes on other worlds. They're highly telepathic and survive by becoming whatever their host family wants them to be, and they don't often kill their foster siblings."

"Well, that's not so bad, then," Jo said. "But it doesn't sound like Addie is becoming everything her parents want her to be, though."

"Yes, I was thinking the same thing." The Doctor leaned forward and rested his elbows on his knees. "Still, it's a possibility."

"So, what you're saying is, we've got to find out if Mrs. Redbarrow is an alien, and what sort of alien, without her knowing that we think she may be an alien. Is that right?"

"Top of the class, Jo." The Doctor grinned and got to his feet.

"And how are we going to do that, exactly?" Jo queried.

The Doctor rubbed the back of his neck. "I suppose we'll just have to do what I always do. Improvise. Come on, Jo. No time like the present" He saw his young assistant's gaze flicker to the police box in the corner of the room. "The TARDIS will take care of her until we get back," he said in response to her unspoken question. "Without knowing Addie's species or what's actually wrong, the TARDIS is better suited to the task than I am at the moment." The Doctor strode to the laboratory doors. "It's time we paid the Redbarrows a visit."

Jo scuttled after him, grabbing both of their coats from the coat rack on her way out.

* * *

A good portion of the drive to their destination consisted of the Doctor and Jo arguing intermittently over how best to infiltrate the Redbarrow's home without suspicion.

"We can leave Bessie a little ways off and say we broke down," Jo chatted excitedly. "Or, I can pretend I'm ill-"

"How much further, Jo?" the Doctor interrupted.

"What? Oh." Jo consulted the map in her lap. "Nearly there, I think." She held it up, and the Doctor squinted at it.

"It's no good; we won't make it."

Jo looked confused. "What do you mean?"

"Well, Jo, old Bessie here is a highly sophisticated vehicle, you know. But she runs on petrol."

"And?"

The old roadster began to sputter. "And we haven't got any," the Doctor stated simply as they came to a stop on the side of the road. He put a hand to his forehead. "I forgot to fill the tank."

Jo glanced up apologetically. "I was supposed to remind you. I'm sorry, Doctor."

The Doctor let out a defeated sigh, but the corner of his mouth twitched into a smile. "It's all right, Jo." He put an arm around her. At least we're only about half a mile out. I don't suppose you fancy another stroll?"

Jo grinned as he gallantly helped her out of Bessie with a theatrical bow.

"Not really dressed for this, are you?" The Doctor commented.

Jo looked down at her decidedly non-winter-appropriate outfit. "At least my boots are somewhat sensible. Oh, Doctor, I'm fine!" she protested as the Doctor slipped out of his driving cloak and draped it over her shoulders.

"Now, look, Jo, I won't have my assistant catching cold. You know I've been only recently reminded how awful it is to be ill."

Jo continued to protest as they walked the last distance to the Redbarrow's address, but the Doctor would hear none of it. "Ooh! You're so stubborn!" She said finally, crossing her arms and sighing in defeat.

The Doctor's eyes twinkled in the rapidly fading sunlight. "Well, you did learn from the best, my dear," he quipped as the odd pair made their way up the dirt-packed drive.

Shivering, Jo was thankful they had made it at last, more for the Doctor's sake than her own. Even under the cloak, she was uncomfortably chilly, and The Doctor couldn't be any warmer than she was. He hid it well as he knocked on the on an old wooden door that looked as though it had been repainted several times, none of which having been recently.

"Let me do the talking, Jo," the Doctor said as light footsteps could be heard from inside. The door swung open, and a tired-looking woman who must have been in her late thirties looked out at them. Jo's heart immediately leaped into her throat as she remembered that the woman's daughter had been missing for several days.

"Good evening, madam," the Doctor greeted her with his boundless charm. "I'm terribly sorry to disturb you, but I'm afraid we've... we've rather..."

Jo glanced up at him in concern as he trailed off. It wasn't like him to become tongue-tied, and she watched in confusion as he patted his pockets briefly. He then furrowed his brow and pressed his fingers to his nose. It was then that Jo realized the trouble, only a split second before the Doctor let out two of the most thunderous sneezes she'd ever heard, nearly causing him to double over.

The woman at the door jumped back in surprise, a hand clutching her chest. "Oh, you poor man!"

"Can you please help us?" Jo implored as she finally found the Doctor's handkerchief in the pocket of his driving cloak. "We've broken down, and he's not well, you see?" She saw the Doctor grimace at having his infirmity pointed out.

"Yes, of course! Come inside!" The woman practically herded the two of them into the house.


End file.
